MONITORING VOICE OVER INTERNET PROTOCOL (VoIP) QUALITY DURING AN ONGOING CALL

ABSTRACT

A method for calculating a mean opinion score (MOS) during an ongoing Voice over Internet Protocol (VoIP) call is provided. The method may include determining a time delay between a VoIP source and a VoIP destination connected by a communications network. A start recording message is sent from the VoIP source to the VoIP destination. A first recorded call sample from the VoIP source and a second recorded call sample from the VoIP destination are generated, whereby the first and the second recorded call sample are generated with a recording delay value corresponding the determined time delay for synchronizing the first and the second recorded call sample. Using an intrusive call quality measurement, a first MOS value is calculated based on the first and the second recorded call sample. Using a non-intrusive call quality measurement, a second MOS value is calculated based on the first MOS value.

BACKGROUND

The present invention generally relates to Voice over Internet Protocol(VoIP), and more particularly, to monitoring the quality of VoIP calls.

VoIP may include technologies for voice communications utilizing avariety of networks, such as the Internet, and network protocols, suchas Internet Protocol (IP). For decades, entities such as phone companieshave used, among other criteria, Mean Opinion Score (MOS) as asubjective but potentially expensive measure of phone call quality.However, such entities may be able to objectively estimate MOS throughat least one of several computational tests. These tests can includenon-intrusive computational methods (e.g., E-Model: Electronic Model)that may be able to be performed during an ongoing call (i.e., on-lineor live) over a communications network. Alternatively, intrusive tests(e.g., PSQM: perceptual speech quality measure) may be utilized toestablish a comparison between a voice signal captured at the senderlocation and a degraded voice signal captured at the receiver location.However, the intrusive test may typically be carried out in an off-lineenvironment (e.g., laboratory) as opposed to during an ongoing livecall.

BRIEF SUMMARY

According to one exemplary embodiment, an enhancement to monitoring thequality of live ongoing calls may include applying a two-stagealgorithmic analysis during a VoIP call between two locations over acommunications network.

According to another exemplary embodiment, a method for calculating amean opinion score (MOS) during an ongoing Voice over Internet Protocol(VoIP) call is provided. The method may include determining a time delaybetween a VoIP source device at a first location and a VoIP destinationdevice at a second location, whereby the first and the second VoIPdevice are connected by a communications network. A start recordingmessage is sent from the VoIP source device to the VoIP destinationdevice. A first recorded call sample from the VoIP source device and asecond recorded call sample from the VoIP destination device aregenerated, whereby the first recorded call sample and the secondrecorded call sample are generated with a recording delay valuecorresponding the determined time delay for synchronizing the first andthe second recorded call sample. Using an intrusive call qualitymeasurement, a first MOS value is calculated, whereby the first MOSvalue is based on the first and the second recorded call sample. Using anon-intrusive call quality measurement, a second MOS value iscalculated, whereby the second MOS value is calculated based on thefirst MOS value.

According to another exemplary embodiment, a computer program productfor monitoring a voice over internet protocol (VoIP) call over acommunications network is provided. The computer program product mayinclude a computer-readable storage device and program instructionsstored on one or more tangible storage devices. The program instructionsare executable by a processor for performing a method that mayaccordingly include determining a time delay between a call sender at afirst location on the communications network and a call receiver at asecond location on the communications network. A first portion of theVoIP call signal originating from the call sender and a second portionof the VoIP call signal at the call receiver are recorded. The firstrecorded portion is synchronized with the second recorded portion tocorrespond to a common call segment associated with the VoIP callbetween the call sender and the call receiver, whereby the firstrecorded portion is synchronized with the second recorded portion basedon the determined time delay. An intrusive call quality measurement isapplied to the first and the second recorded portion for generating afirst output corresponding to the intrusive call quality measurement. Anon-intrusive call quality measurement is applied for generating asecond output based on receiving the first output corresponding to theintrusive call quality measurement and the determined time delayassociated with the communications network.

According to another exemplary embodiment, a computer system formonitoring a voice over internet protocol (VoIP) call over acommunications network is provided. The computer system may include oneor more processors, one or more computer-readable memories, one or morecomputer-readable tangible storage devices, and program instructionsstored on at least one of the one or more storage devices for executionby at least one of the one or more processors via at least one of theone or more memories. The computer system is capable of performing amethod that may accordingly include determining a time delay between acall sender at a first location on the communications network and a callreceiver at a second location on the communications network. A firstportion of the VoIP call signal originating from the call sender and asecond portion of the VoIP call signal originating from the callreceiver are recorded. The first recorded portion is synchronized withthe second recorded portion to correspond to a common call segmentassociated with the VoIP call between the call sender and the callreceiver, whereby the first recorded portion is synchronized with thesecond recorded portion based on the determined time delay. An intrusivecall quality measurement is applied to the first and the second recordedportion for generating a first output corresponding to the intrusivecall quality measurement. A non-intrusive call quality measurement isapplied for generating a second output based on receiving the outputcorresponding to the intrusive call quality measurement and thedetermined time delay associated with the communications network.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

FIG. 1A is a system block diagram of a VoIP call quality monitoringsystem according to one exemplary embodiment;

FIG. 1B is a system block diagram of a VoIP call quality monitoringsystem according to another exemplary embodiment;

FIG. 2 is an exemplary system architecture corresponding to the VoIPcall quality monitoring system of FIG. 1A;

FIG. 3 is an exemplary block diagram of the VoIP monitoring unitutilized within the system architecture diagram of FIG. 2;

FIG. 4 is an operational flow chart corresponding to a VoIP qualitymonitoring (VQM) program according to an exemplary embodiment; and

FIG. 5 is a block diagram of hardware and software for executing theprocess flows of FIG. 4 according to one embodiment.

The drawings are not necessarily to scale. The drawings are merelyschematic representations, not intended to portray specific parametersof the invention. The drawings are intended to depict only typicalembodiments of the invention. In the drawings, like numbering representslike elements.

DETAILED DESCRIPTION

Detailed embodiments of the claimed structures and methods are disclosedherein; however, it can be understood that the disclosed embodiments aremerely illustrative of the claimed structures and methods that may beembodied in various forms. This invention may, however, be embodied inmany different forms and should not be construed as limited to theexemplary embodiments set forth herein. Rather, these exemplaryembodiments are provided so that this disclosure will be thorough andcomplete and will fully convey the scope of this invention to thoseskilled in the art. In the description, details of well-known featuresand techniques may be omitted to avoid unnecessarily obscuring thepresented embodiments.

The one or more exemplary embodiments described herein provide anenhancement to monitoring the quality of live ongoing calls. Inparticular, a two-stage algorithmic analysis is carried out during aVoIP call between two locations over a communications network. In thearea of VoIP, for example, call quality can be measured using eitheron-line, non-intrusive measurement algorithms (e.g., E-model) oroff-line, intrusive measurement algorithms (e.g., POLQA) for the purposeof, among other things, estimating a metric (e.g., MOS) for evaluatingcall quality over data networks. Generally, on-line non-intrusivemeasurement algorithms (e.g., E-model) may determine MOS values that mayreflect estimates of VoIP call quality over a network. Alternative,off-line intrusive measurement algorithms (e.g., POLQA) enable asubstantially accurate MOS determination. However, these off-lineintrusive measurement algorithms may not be used during live calls. Theone or more described exemplary embodiments provide, among other things,a MOS determination process that is both accurate and live (i.e., ableto be used during an ongoing VoIP call).

The present invention may be a system, a method, and/or a computerprogram product. The computer program product may include a computerreadable storage medium (or media) having computer readable programinstructions thereon for causing a processor to carry out aspects of thepresent invention.

The computer readable storage medium can be a tangible device that canretain and store instructions for use by an instruction executiondevice. The computer readable storage medium may be, for example, but isnot limited to, an electronic storage device, a magnetic storage device,an optical storage device, an electromagnetic storage device, asemiconductor storage device, or any suitable combination of theforegoing. A non-exhaustive list of more specific examples of thecomputer readable storage medium includes the following: a portablecomputer diskette, a hard disk, a random access memory (RAM), aread-only memory (ROM), an erasable programmable read-only memory (EPROMor Flash memory), a static random access memory (SRAM), a portablecompact disc read-only memory (CD-ROM), a digital versatile disk (DVD),a memory stick, a floppy disk, a mechanically encoded device such aspunch-cards or raised structures in a groove having instructionsrecorded thereon, and any suitable combination of the foregoing. Acomputer readable storage medium, as used herein, is not to be construedas being transitory signals per se, such as radio waves or other freelypropagating electromagnetic waves, electromagnetic waves propagatingthrough a waveguide or other transmission media (e.g., light pulsespassing through a fiber-optic cable), or electrical signals transmittedthrough a wire.

Computer readable program instructions described herein can bedownloaded to respective computing/processing devices from a computerreadable storage medium or to an external computer or external storagedevice via a network, for example, the Internet, a local area network, awide area network and/or a wireless network. The network may comprisecopper transmission cables, optical transmission fibers, wirelesstransmission, routers, firewalls, switches, gateway computers and/oredge servers. A network adapter card or network interface in eachcomputing/processing device receives computer readable programinstructions from the network and forwards the computer readable programinstructions for storage in a computer readable storage medium withinthe respective computing/processing device.

Computer readable program instructions for carrying out operations ofthe present invention may be assembler instructions,instruction-set-architecture (ISA) instructions, machine instructions,machine dependent instructions, microcode, firmware instructions,state-setting data, or either source code or object code written in anycombination of one or more programming languages, including an objectoriented programming language such as Smalltalk, C++ or the like, andconventional procedural programming languages, such as the “C”programming language or similar programming languages. The computerreadable program instructions may execute entirely on the user'scomputer, partly on the user's computer, as a stand-alone softwarepackage, partly on the user's computer and partly on a remote computeror entirely on the remote computer or server. In the latter scenario,the remote computer may be connected to the user's computer through anytype of network, including a local area network (LAN) or a wide areanetwork (WAN), or the connection may be made to an external computer(for example, through the Internet using an Internet Service Provider).In some embodiments, electronic circuitry including, for example,programmable logic circuitry, field-programmable gate arrays (FPGA), orprogrammable logic arrays (PLA) may execute the computer readableprogram instructions by utilizing state information of the computerreadable program instructions to personalize the electronic circuitry,in order to perform aspects of the present invention.

Aspects of the present invention are described herein with reference toflowchart illustrations and/or block diagrams of methods, apparatus(systems), and computer program products according to embodiments of theinvention. It will be understood that each block of the flowchartillustrations and/or block diagrams, and combinations of blocks in theflowchart illustrations and/or block diagrams, can be implemented bycomputer readable program instructions.

These computer readable program instructions may be provided to aprocessor of a general purpose computer, special purpose computer, orother programmable data processing apparatus to produce a machine, suchthat the instructions, which execute via the processor of the computeror other programmable data processing apparatus, create means forimplementing the functions/acts specified in the flowchart and/or blockdiagram block or blocks. These computer readable program instructionsmay also be stored in a computer readable storage medium that can directa computer, a programmable data processing apparatus, and/or otherdevices to function in a particular manner, such that the computerreadable storage medium having instructions stored therein comprises anarticle of manufacture including instructions which implement aspects ofthe function/act specified in the flowchart and/or block diagram blockor blocks.

The computer readable program instructions may also be loaded onto acomputer, other programmable data processing apparatus, or other deviceto cause a series of operational steps to be performed on the computer,other programmable apparatus or other device to produce a computerimplemented process, such that the instructions which execute on thecomputer, other programmable apparatus, or other device implement thefunctions/acts specified in the flowchart and/or block diagram block orblocks.

The flowchart and block diagrams in the Figures illustrate thearchitecture, functionality, and operation of possible implementationsof systems, methods, and computer program products according to variousembodiments of the present invention. In this regard, each block in theflowchart or block diagrams may represent a module, segment, or portionof instructions, which comprises one or more executable instructions forimplementing the specified logical function(s). In some alternativeimplementations, the functions noted in the block may occur out of theorder noted in the figures. For example, two blocks shown in successionmay, in fact, be executed substantially concurrently, or the blocks maysometimes be executed in the reverse order, depending upon thefunctionality involved. It will also be noted that each block of theblock diagrams and/or flowchart illustration, and combinations of blocksin the block diagrams and/or flowchart illustration, can be implementedby special purpose hardware-based systems that perform the specifiedfunctions or acts or carry out combinations of special purpose hardwareand computer instructions.

Referring to FIG. 1A, a system block diagram of a VoIP call qualitymonitoring system 100A according to one exemplary embodiment isdepicted. The call quality monitoring system 100A may include a VoIPsource device 102A (e.g., a computer, a telephone) and a VoIPdestination device 104A (e.g., a computer, a telephone) that may beconnected by a communications network 108A (e.g., Internet Protocol (IP)network). As depicted, a VoIP monitoring unit 106A (e.g., a computer orprocessing device) may be connected to the communications network 108Ato receive inputs from the VoIP source device 102A and the VoIPdestination device 104A. The VoIP monitoring unit 106A may calculate,for example, a call quality output score (e.g., MOS) from inputsreceived from the VoIP source device 102A, the VoIP destination device104A, and the communications network 108A.

FIG. 1B depicts a system block diagram of a VoIP call quality monitoringsystem 100B according the alternative exemplary embodiment. The VoIPcall quality monitoring system 100B may include a VoIP source device102B (e.g., a computer) and a VoIP destination device 104B (e.g., acomputer) that may be connected by a communications network 108B (e.g.,Internet Protocol (IP) network). As depicted, a VoIP monitoring unit106B may exist as a component within the VoIP source device 102B. TheVoIP monitoring unit 106B may calculate, for example, a call qualityoutput score (e.g., MOS) from inputs received from the VoIP sourcedevice 102B, the VoIP destination device 104B, and the communicationsnetwork 108B. It may be appreciated that VoIP monitoring unit 106A (FIG.1A) and VoIP monitoring unit 106B are substantially identical orsimilar, such that any description of VoIP monitoring unit 106A may alsoapply to VoIP monitoring unit 106B. However, as depicted and describedabove, the location of the VoIP monitoring units 106A, 106B may differaccording to networking preferences and architecture.

Referring to FIG. 2, an exemplary system architecture 200 correspondingto a VoIP call quality monitoring system 100A (FIG. 1A) is depicted. Asillustrated, the system architecture 200 may include a call sender 202(e.g., telephone, computer), a compression codec 204, a communicationsnetwork 206 (e.g., IP network), a de-jitter buffer 208, a decompressioncodec 210, a call receiver 212 (e.g., telephone, computer), a delayaggregation unit 214 (e.g., adder), and a VoIP monitoring unit 106A.

The call sender 202 and the compression codec 204 may, for example, beencapsulated within a VoIP source device 102A (FIG. 1A). Similarly, thede-jitter buffer 208, the decompression codec 210, and the call receiver212 may be encapsulated, for example, within a VoIP destination device104A (FIG. 1A). It may be appreciated that by further encapsulating theVoIP monitoring unit 106A within the VoIP source device 102A, a systemarchitecture for VoIP source device 102B (FIG. 1B) may be described.Furthermore, it may be appreciated that the system architecture for VoIPdestination device 104A may be used to describe a system architecturefor VoIP destination device 104B (FIG. 1B).

In a call scenario, the call sender 202 may capture voice data, whichmay be encoded and packetized by the compression codec 204. The voicedata may then be transmitted via the communications network 206 to thecall receiver 212. Prior to the call receiver 212 playing back thetransmitted voice data received from the call sender 202, thetransmitted voice data may be subjected to de-jittering by de-jitterbuffer 208. Subsequently, the de-jittered transmitted voice data may bedecoded and depacketized by the decompression codec 210. Upondecompression, the decoded and depacketized voice data may be playedback by the call receiver 212.

During an established call between call sender 202 and call receiver212, a portion of the call is recorded at both the call sender 202 andthe call receiver 212 in a synchronized manner. The synchronizedrecording ensures that the call sender 202 and the call receiver 212capture and record the same segment or portion of the call. For example,if the segment of the call includes voice data associated with thephrase “hello mother” generated by the call sender 202, the same segmentat the call receiver 212 will accordingly be the same generated “hellomother” phrase. A “Start Recording Message” command encapsulated withina user datagram protocol (UDP) packet is sent from the call sender 202to the call receiver 212 over the communications network 206 for thepurpose of facilitating the synchronized recording. The call receiver212 may begin recording a portion of the call (e.g., received “hellomother” phrase) upon receiving the “Start Recording Message” UDP packet.Also, upon sending the “Start Recording Message” UDP packet, the callsender 202 begins recording the portion of the call (e.g., generated“hello mother” phrase). Thus, the recording times at the call sender 202and call receiver 212 are synchronized to capture the same call segment(e.g., “hello mother” phrase). Accordingly, the first recorded VoIP calland the second recorded VoIP call are synchronized based on a time delayvalue t_(d) associated with voice packets being transmitted between thecall sender 202 and the call receiver 212. Since the “Start RecordingMessage” command is subject to the same delay (e.g., t_(d)) as the voicedata sent between the call sender 202 and the call receiver 212,substantially identical call segments or portions (e.g., “hello mother”)are recorded.

A delay aggregation unit 214 (e.g., an adder) may be used to determinethe time delay value t_(d) between the call sender 202 and the callreceiver 212 connected across the communications network 206. The delayaggregation unit 214 may, therefore, determine any accumulated delaysencountered by VoIP packets between the call sender 202 and callreceiver 212. The time delay value t_(d) may include an aggregate valuecorresponding to a capture and encoding delay t₀ associated with callsender 202 and compression codec 204, a propagation delay t₁ associatedwith communications network 206, a de-jitter buffer delay t₂ associatedwith de-jitter buffer 208, and a decoding and playback delay t₃associated with decompression codec 210 and call receiver 212. Asdepicted, the delay aggregation unit 214 may include a networked devicein communication with various other network elements (e.g., Codecs,network monitoring software, de-jitter buffers, etc.) via communicationsnetwork 206. In alternative implementations, the delay aggregation unit214 may reside within, for example, VoIP monitoring unit 106A.

The VoIP monitoring unit 106A may be connected to the call sender 202,the communications network 206, the call receiver 212, and the delayaggregation unit 214. The VoIP monitoring unit 106A may receive a firstrecorded portion of the VoIP call (e.g., generated “hello mother”phrase) from the call sender 202 over data link 222. Similarly, the VoIPmonitoring unit 106A may receive a second recorded portion of the VoIPcall (e.g., received “hello mother” phrase) from the call receiver 212over data link 224. The VoIP monitoring unit 106A may optionally receivequality of service (QoS) parameters (e.g., packet loss, jitter) from thecommunications network 206 over data link 220. As described in thefollowing paragraphs, QoS parameters may not be necessary fordetermining voice quality based on the two-stage algorithmic processingcarried out. The depicted dashed lines are indicative of an optional orconventional use of the QoS parameters when, for example, only aconventional single non-intrusive call quality measurement is made. TheVoIP monitoring unit 106A may further receive time delay value t_(d)from the delay aggregation unit 214 over data link 226. The VoIPmonitoring unit 106A may be implemented as software, hardware, firmware,or any combination thereof. Furthermore, as previously indicated, thedelay aggregation unit 214 and the VoIP monitoring unit 106A may beencapsulated within a single unit. For data links 220, 222, 224, and226, any desired medium (e.g., wireless or wired) or protocol (e.g., IPor Transmission Control Protocol) may be used. Accordingly, the VoIPmonitoring unit 106A processes the received first and the secondrecorded portion of the VoIP call (i.e., common call segment), thereceived QoS parameters, and the received time delay value t_(d) inorder to determine the call quality of a VoIP call between the callsender 202 and the call receiver 212. An exemplary VoIP monitoring unit106A is illustrated and described in relation to FIG. 3. For example,the first recorded portion of the VoIP call (e.g., generated “hellomother” phrase) originating from the call sender 202, and the secondrecorded portion of the VoIP call (e.g., received “hello mother” phrase)generated at call receiver 212, may be sent along respective data links222 and 224 using any lossless protocol such as Transmission ControlProtocol (TCP).

In operation, the call sender 202 may be used to capture call voice dataand convert the call voice data to a digital waveform. The compressioncodec 204 may encode this voice data into a series of data packets thatmay be more easily sent over existing communications standards, such asTCP, UDP, or Internet Protocol (IP). The packetization of the call voicedata would be subject to the capture and packetization to delay based onthe type of codec used for compression, where value of t₀ may be theamount of time taken for call voice data to be captured by the callsender 202 and encoded and packetized by the compression codec 204.After compression by the compression codec 204, the voice data packetswould be transmitted over a communications network 206 that may use aUDP protocol. The transmitted voice data packets may be subjected to thepropagation delay t₁, where value of t₁ may be the amount of time takenfor a voice data packet to be sent from the compression codec 204 andreceived by the de-jitter buffer 208 over the communications network206.

The de-jitter buffer 208 may receive the voice data packets from thecommunications network 206 and artificially add a delay value t₂ tominimize the variance in voice data packet arrival times. Thede-jittered voice data packets may then be de-packetized by thedecompression codec 210 to convert the packetized digital waveform intoraw digital data that can be converted to an analog signal and playedback by the call receiver 212. This conversion from voice data packetsto analog voice signal may be subjected to the depacketization andplayback delay t₃, where the value of t₃ corresponds to an amount oftime needed for the decompression codec 210 to decode and depacketizethe voice data packets into raw digital data.

FIG. 3 is an exemplary block diagram of the VoIP monitoring unit 106Autilized within the system architecture diagram 200 of FIG. 2. Asdepicted, the VoIP monitoring unit 106A may include an optional qualityof service (QoS) parameter acquisition and measurement unit 302, anintrusive quality measurement unit 304, and a non-intrusive qualitymeasurement unit 306.

As indicated above, the QoS parameters may not be necessary fordetermining voice quality based on the two-stage algorithmic processingcarried out according to one or more exemplary embodiments describedherein. The depicted dashed lines are indicative of an optional orconventional use of the QoS parameters when, for example, only aconventional single non-intrusive call quality measurement is made.Accordingly, an optional QoS parameter acquisition and measurement unit302 may determine a variety of QoS parameters corresponding to a networksuch as communications network 206 (FIG. 2). The QoS parameters mayinclude a packet loss determination and a jitter determination that arereceived from the communications network 206 (FIG. 2.) via optional datalink 220. The acquired QoS parameters may be sent from the QoS parameteracquisition and measurement unit 302 to the non-intrusive qualitymeasurement unit 306 via optional data link 310. According to oneimplementation, the QoS parameter acquisition and measurement unit 302polls QoS parameters from the communications network 206 (FIG. 2).According to an alternative implementation, the QoS parameteracquisition and measurement unit 302 may include network monitoringsoftware that, at least in part, generates the QoS parameters.

The intrusive quality measurement unit 304 may, for example, calculate afirst mean opinion score (MOS) for VoIP call quality using an intrusivecall quality algorithm such as a perceptual speech quality measure(PSQM) algorithm, a perceptual evaluation of speech quality (PESQ)algorithm, or a perceptual objective listening quality assessment(POLQA) algorithm. The intrusive quality measurement unit 304 maycalculate the first MOS using a first recorded portion of a VoIP callgenerated by call sender 202 (FIG. 2) and a second recorded portion of aVoIP call generated by call receiver 212 (FIG. 2). The first and thesecond recorded portion of the VoIP call may be input to the intrusivequality measurement unit 304 using respective data links 222 and 224(also see FIG. 2.). The intrusive quality measurement unit 304 mayanalyze a synchronized common call segment (e.g., “hello mother”)corresponding to the first and the second recorded portion of the VoIPcall and evaluate characteristics of the synchronized common callsegment using an intrusive call quality algorithm in order to generate afirst MOS. The first MOS may then be sent by the intrusive qualitymeasurement unit 304 to the non-intrusive quality measurement unit 306via data link 312.

The non-intrusive quality measurement unit 306 may, for example,calculate a second MOS for VoIP call quality measurement using anon-intrusive call quality algorithm (e.g., E-model). The non-intrusivequality measurement unit 306 may receive the first MOS generated by theintrusive quality measurement unit 304 as an input for the non-intrusivecall quality algorithm via data link 312. The non-intrusive qualitymeasurement unit 306 may also receive the time delay input t_(d) fromthe delay aggregation unit 214 (FIG. 2) via data link 226. Thenon-intrusive quality measurement unit 306 may output a second MOS formonitoring VoIP call quality via data link 308. The second MOS on datalink 308 may be utilized as a final MOS for the VoIP call. Accordingly,the final MOS provides a call quality measure that depends on one MOScalculation (i.e., first stage) being used to generate another MOS(i.e., second stage). Thus, the two-stage MOS calculation provided bythe intrusive quality measurement unit 304 (i.e., first stage) and thenon-intrusive quality measurement unit 306 (i.e., second stage)mitigates the need for processing QoS parameters at the second stagenon-intrusive quality measurement unit 306. This occurs as a result ofthe first stage processing provided by intrusive quality measurementunit 304 inherently considering QoS parameters such as jitter and packetloss. The inherent QoS considerations stem from the intrusive qualitymeasurement unit 304 comparing common voice data at separate locations(i.e., sender 202 and receiver 212) on the communications network 206.Thus, packet loss and jitter effects are reflected in the compared voicedata.

FIG. 4 is an operational flow chart corresponding to a VoIP qualitymonitoring program 400 corresponding to the exemplary embodimentdepicted in FIG. 2. The VoIP quality monitoring program 400 of FIG. 4 isdescribed with the aid of the exemplary embodiments of FIGS. 2 and 3.

At 402, a time delay value between a call sender and a call receiver isdetermined. For example, a delay aggregation unit 214 (FIG. 2) such asan adder may determine a time delay value t_(d) between a call sender202 (FIG. 2) and a call receiver 212 (FIG. 2) connected across acommunications network 206 (FIG. 2). The delay aggregation 214 unit maydetermine an aggregate value corresponding to the capture and encodingdelay t₀ associated with call sender 202 and compression codec 204 (FIG.2), the propagation delay t₁ associated with communications network 206,the de-jitter buffer delay t₂ associated with de-jitter buffer 208 (FIG.2), and the decoding and playback delay t₃ associated with decompressioncodec 210 (FIG. 2) and call receiver 212.

At 404, a start recording message is sent from the call sender to thecall receiver. For example, the call sender 202 may send a “StartRecording Message” packet over the communications network 206 to thecall receiver 212. This “Start Recording Message” may be of anyprotocol, such as UDP.

At 406, a first portion of a VoIP call between the call sender and thecall receiver is recorded. The first portion of the VoIP call originatesat the call sender and is recorded upon the sending of the startrecording message. For example, once the “Start Recording Message” UDPpacket is sent by the call sender 202 to the call receiver 212, the callsender 202 beings to record a first portion of the ongoing VoIP call(e.g., generated “hello mother” phrase) between the call sender 202 andthe call receiver 212.

At 408, a second portion of the VoIP call between the call sender andthe call receiver is recorded. The second portion of VoIP call isrecorded at the call receiver upon the start recording message arrivingat the call receiver, such that the first and the second portion of theVoIP call substantially apply to a common call segment. For example,once the “Start Recording Message” UDP packet is received by the callreceiver 212, the call receiver 212 beings to record a second portion ofthe ongoing VoIP call (e.g., received “hello mother” phrase) between thecall sender 202 and the call receiver 212. This second portion of theongoing VoIP call may correspond to a common segment of the ongoing VoIPcall, such that the first portion recorded by the call sender 202 andthe second portion recorded by the call receiver 212 are substantiallythe same.

At 410, an intrusive call quality measurement is applied to the firstand the second recorded portion of the VoIP call in order to generate afirst MOS value. For example, once the first recorded portion of theVoIP call is obtained by the call sender 202 and the second recordedportion of the VoIP call is obtained by the call receiver 212, anintrusive call quality measurement algorithm (e.g., POLQA) is applied bythe intrusive quality measurement unit 304 (FIG. 3). The intrusivequality measurement unit 304 may receive the first recorded portion ofthe VoIP call from the call sender 202 (FIG. 2) over data link 222 (FIG.3) and the second recorded portion of the VoIP call from the callreceiver 212 (FIG. 2) over data link 224 (FIG. 3). The intrusive qualitymeasurement unit 304 may then generate a first MOS, corresponding to thefirst and the second recorded portion of the VoIP call.

At 412, a non-intrusive call quality measurement is applied to thegenerated first MOS and the determined time delay to generate a finalMOS value. For example, the non-intrusive quality measurement unit 306(FIG. 3) may receive the first generated MOS from the intrusive qualitymeasurement unit 304 (FIG. 3) via data link 312 (FIG. 3). Thenon-intrusive quality measurement unit 306 may also receive the timedelay value t_(d) from the delay aggregation unit 214 (FIG. 2) via datalink 226 (FIG. 3). The non-intrusive quality measurement unit 306 maythen output a second MOS value corresponding to the first MOS value, thedelay t_(d), and the QoS parameters over data link 308 (FIG. 3).

FIG. 5 shows a block diagram of the components of a data processingsystem 800, 900, that may be incorporated within VoIP monitoring unit106A (FIG. 2) in accordance with an illustrative embodiment of thepresent invention. It should be appreciated that FIG. 5 provides only anillustration of one implementation and does not imply any limitationswith regard to the environments in which different embodiments may beimplemented. Many modifications to the depicted environments may be madebased on design and implementation requirements.

Data processing system 800, 900 is representative of any electronicdevice capable of executing machine-readable program instructions. Dataprocessing system 800, 900 may be representative of a smart phone, acomputer system, PDA, or other electronic devices. Examples of computingsystems, environments, and/or configurations that may represented bydata processing system 800, 900 include, but are not limited to,personal computer systems, server computer systems, thin clients, thickclients, hand-held or laptop devices, multiprocessor systems,microprocessor-based systems, network PCs, minicomputer systems, anddistributed cloud computing environments that include any of the abovesystems or devices.

The data processing system 800, 900 may include may include a set ofinternal components 800 and a set of external components 900 illustratedin FIG. 5. The set of internal components 800 includes one or moreprocessors 820, one or more computer-readable RAMs 822 and one or morecomputer-readable ROMs 824 on one or more buses 826, and one or moreoperating systems 828 and one or more computer-readable tangible storagedevices 830. The one or more operating systems 828 and programs such asthe VoIP quality monitoring (VQM) program 400 is stored on one or morecomputer-readable tangible storage devices 830 for execution by one ormore processors 820 via one or more RAMs 822 (which typically includecache memory). In the embodiment illustrated in FIG. 5, each of thecomputer-readable tangible storage devices 830 is a magnetic diskstorage device of an internal hard drive. Alternatively, each of thecomputer-readable tangible storage devices 830 is a semiconductorstorage device such as ROM 824, EPROM, flash memory or any othercomputer-readable tangible storage device that can store a computerprogram and digital information.

The set of internal components 800 also includes a R/W drive orinterface 832 to read from and write to one or more portablecomputer-readable tangible storage devices 936 such as a CD-ROM, DVD,memory stick, magnetic tape, magnetic disk, optical disk orsemiconductor storage device. The VQM program 400 can be stored on oneor more of the respective portable computer-readable tangible storagedevices 936, read via the respective R/W drive or interface 832 andloaded into the respective hard drive 830.

The set of internal components 800 may also include network adapters (orswitch port cards) or interfaces 836 such as a TCP/IP adapter cards,wireless wi-fi interface cards, or 3G or 4G wireless interface cards orother wired or wireless communication links. VQM program 400 can bedownloaded from an external computer (e.g., server) via a network (forexample, the Internet, a local area network or other, wide area network)and respective network adapters or interfaces 836. From the networkadapters (or switch port adaptors) or interfaces 836, the VQM program400 is loaded into the respective hard drive 830. The network maycomprise copper wires, optical fibers, wireless transmission, routers,firewalls, switches, gateway computers and/or edge servers.

The set of external components 900 can include a computer displaymonitor 920, a keyboard 930, and a computer mouse 934. The set ofexternal components 900 can also include touch screens, virtualkeyboards, touch pads, pointing devices, and other human interfacedevices. The set of internal components 800 also includes device drivers840 to interface to computer display monitor 920, keyboard 930 andcomputer mouse 934. The device drivers 840, R/W drive or interface 832and network adapter or interface 836 comprise hardware and software(stored in storage device 830 and/or ROM 824).

The descriptions of the various embodiments of the present inventionhave been presented for purposes of illustration, but are not intendedto be exhaustive or limited to the embodiments disclosed. Manymodifications and variations will be apparent to those of ordinary skillin the art without departing from the scope and spirit of the describedembodiments. The terminology used herein was chosen to best explain theprinciples of the one or more embodiment, the practical application ortechnical improvement over technologies found in the marketplace, or toenable others of ordinary skill in the art to understand the embodimentsdisclosed herein.

What is claimed is:
 1. A method for calculating a mean opinion score(MOS) during an ongoing Voice over Internet Protocol (VoIP) call,comprising: determining a time delay between a VoIP source device at afirst location and a VoIP destination device at a second location, thefirst and the second VoIP device connected by a communications network;sending a start recording message from the VoIP source device to theVoIP destination device; generating a first portion of a recorded VoIPcall from the VoIP source device and a second portion of a recorded VoIPcall from the VoIP destination device, wherein the first recorded VoIPcall and the second recorded VoIP call are generated based on thedetermined time delay for synchronizing the first and the secondrecorded VoIP call to apply to a common call segment; calculating, usingan intrusive call quality measurement, a first MOS value, wherein thefirst MOS value is based on the first and the second recorded callsample; and calculating, using a non-intrusive call quality measurement,a second MOS value, wherein the second MOS value is calculated based onthe first MOS value.
 2. The method of claim 1, wherein the determiningof the time delay comprises: determining a capture and compression delayvalue associated with the VoIP source device; determining a propagationdelay value associated with the communications network; determining ade-jitter buffer delay value associated with the VoIP destinationdevice; determining a decompression and playback delay value associatedwith the VoIP destination device; and determining an aggregate value ofthe capture and compression delay value, the propagation delay value,the de-jitter buffer delay value, and the decompression and playbackdelay value.
 3. The method of claim 1, wherein inputs to the intrusivetesting method comprise: the first recorded call sample; and the secondrecorded call sample.
 4. The method of claim 1, wherein inputs to thenon-intrusive testing method comprise: the calculated first MOS value;and the determined time delay value.
 5. The method of claim 1, whereinthe intrusive call quality measurement accounts for a packet loss and ajitter value associated with a quality of service (QoS) determination.6. The method of claim 1, wherein the intrusive testing method comprisesone of a perceptual speech quality measure (PSQM) algorithm, aperceptual evaluation of speech quality (PESQ) algorithm, and aperceptual objective listening quality assessment (POLQA) algorithm. 7.The method of claim 1, wherein the non-intrusive testing methodcomprises an electronic model (E-model) testing algorithm.